Gat first came to prominence as the guitarist and founder of Monotonix. After finding themselves banned from most venues in their country due to the wild and controversial nature of their concerts, the band decided to leave Israel and tour the United States and Europe. With Monotonix, Gat released an EP and two albums on Drag City Records. Gat's guitar was the only harmonic instrument in the drums-guitar-vocals power trio and was singled out by the likes of Pitchfork mentioning "guitarist Yonatan Gat slides in and out of solos without ever throwing the rhythm off the rails... The descending guitar line that follows is sweet and yearning enough to fit onto a damn Strokes record." During the band's 5-year existence, Gat played 1,000 concerts as its guitarist and co-founder, collaborating with musicians such as Fugazi's Ian Mackaye and Guy Picciotto and Beat Happening and K Records founder Calvin Johnson, while touring as support for Pavement, Faith No More and Silver Jews. The latter's frontman David Berman would go on to co-produce Gat's 2018 sophomore LP Universalists. Songs by Monotonix were used in TV, film and video games such as House, Grand Theft Auto and Better Living Through Chemistry. In 2008, Monotonix were called "the most exciting live band in rock 'n' roll" by Spin Magazine and by 2011, after completing a world tour for the final album, Not Yet, they stopped touring, allowing Gat to focus on his career as a solo artist.
After Monotonix's final world tours in 2011, Gat settled in New York and began recording and performing as a bandleader and solo artist, engaging Gal Lazer and Sergio Sayeg as his core studio-collaborators while expanding his projects to include musicians such as Brian Chase, Greg Saunier and Thor Harris. Gat began touring the United States and Europe both as headliner and sharing the stage with artists such as Thee Oh Sees and Sun Ra Arkestra, often performing his set on the floor in the middle of the audience. He released his debut EP, Iberian Passage, written and recorded while he was living in Portugal, in the spring of 2014 on Joyful Noise Recordings and his full-length studio album debut, Director, followed in 2015. Within months of Director's premiere, an EP produced by Steve Albini titled Physical Copy followed. Gat's latest album, Universalists, was released through Joyful Noise Records on May 4, 2018. In that same year he went on to release a split 7-inch with Os Mutantes, be featured as guest guitarist on legendary Nigerien band Tal National's new album, and premiere a collaboration with a Rhode IslandAlgonquinpowwow drum ensemble – the Eastern Medicine Singers. The album's release was followed by a world tour with Gat backed by an 8-piece band which included members of his own ensemble of long-time collaborators, as well as the Native American drummers and singers of the Eastern Medicine Singers.